Some are easier to frag than others depending on the particular rock they are on, and how thick they may be. If they are on a smooth surface, with care, slide a new razor blade underneath the start of the mat (if it is a mat) then try gently pulling them off. Once off, you can easily take the razor and partition them up. After that, glue them onto small pieces of rubble patted dry with superglue gel. Although I must say, the best way is that described above. Letting them do it themselves by rubble placement around the mother colony. Make sure to put the rubble above the colony as they will grow best towards the light.